Graduated blur filter

Technical question:

Does anyone have any ideas on how I can create, in PhotoShop, a graduated gaussian blur matte or layer? I am thinking here of the following situation:
I have a foreground subject in focus, but the background, which falls away to infinity, is too "in focus" thanks to a large DOF at exposure. I want to select the background, then create a matte or layer of it, then blur it with a gradient--more blur toward the top of the image (the distant background) and less at the bottom. Sounds simple....

thanks for any thoughts.

cheers,

Here's how I do it.

Create a new layer. Copy the original image (or the background cut-out, you get the idea) to this new layer. Do a gaussian blur on the layer. The radius you select will be the radius where the picture is blurred most.

Select in the menu 'Layer -> Add Layer Mask -> Reveal All'. Click on the mask next to the new layer in the layers palette. Change your foreground color to black. Select the Gradient Tool. Now select the 'foreground to transparent' gradient option. Draw a line in the mask; start where you want it to blur the least, stop where you want it to blur the most (the line doesn't neccesarily have to cover the whole picture).

Now right-click on your mask and select 'Apply layer mask'. That's it, you should have a nice graduated blur now . Hope this helps.